1996 Chevy Lumina FUEL PUMP/PCM COMPUTER

I RECENTLY HAD SOME WORK DONE ON MY LUMINA. THE MECHANIC SAID THE FUEL PUMP WENT OUT. HE WAS IN THE PROCESS OF WORKING ON THE CAR AND SOME HOW MANAGED TO CONTINOUSLY BURN THE RELAY. THIS CAUSED AN ELECTRICAL PROBLEM AND BURNED THE PCM MODGULE. THEM HE INFORMED ME THAT THE PCM COMPUTER WOULD NEED TO BE REPLACED. OUNCE THAT WAS DONE I GOT MY CAR BACK. HE INFORMED ME TO GET A OIL CHECK AND I DID. AND AFTER THAT IT RAN GREAT. BUT JUST FOR A DAY! IT BROKE DOWN AGAIN AND NOW IM CONFUSED AS TO WHY! IS IT THE PCM? IS IT FUEL PUMP? OR SOMETHING ELSE ALL TOGETHER?